I was looking through Wikipedia's unidentified images (stickied here) and I came across this image of a large cenotaph or memorial. Something about this image caught my attention, and I've come up with a few pointers.

The double-headed eagle engraving game me idea of a 'January Effect' - where the object can both see into the past and look to the future (like the Roman God Janus). When a subject touches the tomb, very small engravings appear on the two long sides. This usually causes minor after-effects on the subject, like passing out or minor burns to the hands.

On the opposite side, a detailed inscription of the subject's family tree will appear, centered around the subject. The tree can be of arbitrary length. Sometimes it will show only direct ancestors/descendants, other times stretching back multiple generations. The length of this could be determined by some sort of factor, like subject interest is family history? I haven't thought this bit out. Could also maybe expand this to allow modification of trees, maybe introducing temporal issues?

The main feature is that, on the eagle side, the subject's name will appear above it. Below it will either be a date of death (either as specific as a time/date or as vague as a general year) or cause of death (again, with varying levels of detail). The conditions presented are absolute, and will be met. However, subject's attempts as prolonging their life or avoiding the cause of death will ultimately lead to an unwitting self-fulfilling scenario - where the subject inadvertently fulfills the condition presented.

An interesting take relating to genealogy tree could be the greatest achievement accomplished of each member, or the most important act they have done when faced with death. Calm deaths could have something like a generous donation and brutal death saving someone. The subject's name, instead of offering cause or time of death, could offer a hint on how to achieve the most when their time will come or the greatest accomplishment the can do, with a cryptic hint how to do it.